The invention lies generally in the field of systems wherein data is gathered pertaining to the statuses of a plurality of inputs, lies more particularly in the type of such systems wherein the inputs are scanned one at a time in a prescribed sequence and wherein input status data on successively scanned inputs is detected by an output common to all inputs, and lies still more particularly in the type of such systems wherein the data detected by the common output is stored in memory having addressable memory locations to which the common output data is steered for storage according to generated memory location addresses.
In the prior art of such systems as the above, such as U.S. Pat. No. 3,546,678 to W. B. Callaway et al. of Dec. 8, 1970 and such as U.S. Pat. No. 3,732,547 to R. H. Etra of May 8, 1973, it has been necessary to advance memory access in synchronism with input scanning so that with respect to successively scanned inputs or to successively scanned groups of inputs the related status data on the common output has been steered into the corresponding memory locations by virtue of the synchronism between the scanned input positions and the corresponding memory location access. With regard particularly to the storage of status data for groups of inputs, it has been necessary either to parallel all inputs of a group so that any status data for the group appears on the common output at one particular scanned input position corresponding to one particular memory location or to dedicate certain scanned input positions to memory locations for groups of inputs whose status data is accumulated externally of the memory and steered into the memory locations corresponding to the dedicated scanned input positions.
While the above prior types of input grouping arrangements have proven quite workable, there is a constant effort made to provide grouping arrangements which do not depend upon paralleling grouped inputs to particular scanned input positions and which do not require the dedicated use of input positions to define input groupings.
The prior art has provided an arrangement for employing a control memory word for each scanned input position where each control word includes instructions defining the accumulator memory location address of the input grouping for each scanned input so that accumulator memory access circuitry can be controlled according to the preassigned memory location addresses of specified input groups. An example of the latter type of input grouping arrangement is found in U.S. Pat. No. 3,982,232 to R. H. Etra of Sept. 21, 1976. An arrangement such as in the Etra application precludes the necessity for paralleling grouped inputs to particular scanned input positions and precludes the necessity for dedicated use of input positions to define input groupings; but, such an arrangement requires synchronization of scanning with access to control word memory location and requires additional circuitry for using the control word for subsequently accessing accumulator memory.
The present invention precludes the necessity for synchronization of input scanning with corresponding input memory access, precludes the necessity for paralleling groups of inputs to particular scanned input positions, and precludes the necessity for dedicated use of input position to define input groupings.